Method for making a composite extruded profile formed with thermoplastic organic material reinforced with reinforcing fibres

ABSTRACT

A process for manufacturing a composite profile based on a thermoplastic organic material reinforced by reinforcing fibres includes making a multiplicity of continuous reinforcing yarns come into contact with a thermoplastic organic material and shaping the composite profile. Continuous yarns based on continuous glass fibres and on a first thermoplastic are brought together to be parallel and at least one consolidated tape is formed by heating them, in which tape the reinforcing fibres are impregnated with the first thermoplastic. The at least one tape is introduced into a die sized to the cross-section of the profile and at least one second molten thermoplastic organic material is simultaneously introduced into the die in contact with the tape, to obtain a profile of at least one second thermoplastic organic material reinforced by the at least one tape.

BACKGROUND OF THE INVENTION

1. Field of Invention

The invention relates to the manufacture of a composite profile based ona thermoplastic organic material reinforced with reinforcing fibres.

2. Discussion of the Background

For the sake of lightening a wide range of products, it is commonpractice to manufacture articles from plastic instead of more densematerials, the plastic being intrinsically reinforced, especially withfibrous reinforcements, in order to maintain the mechanical strength ofthe product.

It is known to use reinforcements comprising short fibres which aremixed directly with the plastic or are introduced in the form ofcomposites such as granules comprising the reinforcements in a resin orplastic matrix. However, these short fibres do not make it possible toproduce all the desired types of reinforcements, especially those forincreasing the flexural strength of articles in one direction by acertain extent.

There are reinforcements based on continuous fibres in the form ofcloths or fabrics more especially suitable for the manufacture ofarticles by moulding.

The incorporation of continuous reinforcing fibres into a profiledarticle, characterized by a long length compared with its other twodimensions, continues, however, to raise a few difficulties. This isbecause the technique of moulding is expensive and it appears to bedesirable to develop other manufacturing solutions.

Patent Application FR 2,516,441 discloses a process for manufacturingthin profiles comprising unidirectional continuous glass fibres embeddedin a thermoplastic resin.

The steps of the process for obtaining such profiles are as follows:

-   -   unwinding glass yarns from wound packages, in order to form a        sheet of yarns;    -   separating the fibres of the yarns, in order to separate them        because of the size with which they are coated;    -   dipping the sheet of glass fibres into an aqueous bath of a        thermoplastic or else into a fluidized bed of powder of a        thermoplastic;    -   heating the sheet in order to evaporate the water or to melt the        powder, depending on the mode of dipping;    -   hot-shaping the resin-encapsulated sheet of fibres so as to        produce the desired section.

One drawback with this process is that it is necessary, in order for thefibres to be uniformly impregnated with the thermoplastic, to introducethe step of separating the fibres. This requires a specific device usingseveral rollers, the number and arrangement of which, for ensuring thesuitable winding angle of the sheet on these rollers, are determined bythe degree to which the fibres stick together.

In addition, it is sometimes necessary, when the degree of sticking istoo high, to provide heating means complementary to the rollers.

Consequently, there is a possibility that all the fibres are notcompletely separated from each other, in order subsequently to allowthem to be encapsulated with the thermoplastic.

Moreover, the process uses for the impregnation a bath of athermoplastic which has to be maintained at a constant level, thedispersion of which thermoplastic is constantly circulated in order toensure as constant an impregnation as possible. Furthermore, the meansemployed in this bath are considerable and difficult to manage in amanufacturing line; these are elements such as a liquid delivery pump, aweir for establishing a constant level, a storage tank for the overflow,and a stirring device for ensuring that the contents of the bath arehomogeneous, these elements having to be regularly cleaned.

In the variant of the impregnation device for the use of a fluidizedbed, specific means are also necessary, especially a vibrating systemmounted on springs, for metering the amount of powder taken away by thefibres.

Finally, the shaping device consists of a lower roller provided with agroove through which the sheet runs and of an upper roller serving topress the sheet. Thus, the various expected gauges of the profile entailthe drawback of having to have available several rollers which havevariously sized grooves, respectively.

Consequently, this process, being slow to carry out, proves to beexpensive and of low performance.

This process is furthermore limited to the production of thin profilesand offers little freedom as regards the design of the cross section ofthe profile, especially if it is desired to adjust the amount of plasticin certain portions of the profiled cross section.

The object of the present invention is therefore to provide a processfor manufacturing a composite profile based on a thermoplastic organicmaterial reinforced by reinforcing fibres, which is easy and rapid toimplement, as well as being economic from the industrial standpoint.

More particularly, the invention provides, by virtue of this process, aproduct in the form of a profile consisting, on the one hand, of atleast one tape of continuous reinforcing yarns arranged so as to beapproximately parallel and touching each other and consolidated by afirst thermoplastic and, on the other hand, of at least one secondplastic in intimate contact with the said tape(s).

SUMMARY OF THE INVENTION

According to the invention, the process for manufacturing the tape ischaracterized in that it comprises at least the following steps:

-   -   continuous yarns based on continuous glass fibres and on a first        thermoplastic are brought together so as to be parallel and at        least one consolidated tape is formed by heating them, in which        tape the reinforcing fibres are impregnated with the first        thermoplastic; and    -   at least one tape is introduced into a die sized to the cross        section of the profile and at least one second molten        thermoplastic organic material is simultaneously introduced into        the said die in contact with the tape or tapes, so as to obtain        a profile consisting of at least one second thermoplastic        organic material reinforced by at least one tape.

As will also be explained below, the term “tape” is understood withinthe meaning of the present description to be a material in the form of astrip, which may be essentially flat, or may have a shape of morecomplex cross section in which each portion can be likened to a strip.

The tape may be flexible, especially capable of being wound when thetape is essentially flat, or may be more or less rigid.

Moreover, the term “consolidated” is understood to mean that the glassfibres are impregnated with the first thermoplastic so that the tape hasa certain cohesion and an integrity which make it possible for it to behandled without being damaged.

According to the invention, the preliminary manufacture of aconsolidated reinforcement guarantees integration of the reinforcementin the desired form and with the desired geometry in the profile, andthe impregnation with the first thermoplastic guarantees, moreover, truebonding of the reinforcement to the second thermoplastic orthermoplastics of which the body of the profile is composed.

According to one particular method of implementation, the tape is formedfrom continuous yarns comprising glass yarns and organic fibres of thesaid first thermoplastic.

According to a preferred characteristic, the yarns which are broughttogether consist of continuous glass filaments and continuousthermoplastic filaments which are co-mingled together. The intimatestructure of these yarns facilitates the impregnation of the glassfibres with the thermoplastic and in particular it improves theuniformity of the impregnation in order to form a consolidated tapewhich is itself very uniform.

The said first thermoplastic may be chosen from polyolefins, especiallypolyethylene and polypropylene, and from polyesters, especiallypolyethylene terephthalate and polybutylene terephthalate.

According to one particular method of implementation, for forming thetape:

-   -   yarns based on the first thermoplastic and on glass fibres are        entrained and brought together in a parallel manner in the form        of at least one sheet;    -   at least one sheet is made to enter a zone in which it is heated        to a temperature reaching at least the melting point of the        first thermoplastic without reaching the softening temperature        of the reinforcing fibres;    -   at least one sheet is made to pass through an impregnation        device, while maintaining its temperature at a temperature at        which the first thermoplastic is malleable, in order to        distribute the first molten thermoplastic uniformly and to        impregnate the glass fibres therewith.

According to another characteristic, at least one sheet is introducedinto a first shaping device, while maintaining its temperature at atemperature at which the first thermoplastic is malleable, so as toobtain at least one tape formed by bringing the yarns together so as tobe touching, thereby creating transverse continuity.

According to another characteristic, the process comprises a stepconsisting in unreeling, from wound packages, a continuous yarn ofreinforcing filaments and filaments of the first thermoplastic and,while the yarns are being brought together in the form of a sheet, inregulating the tension in the yarns.

Advantageously, the yarns are stripped of any static electricity beforethe sheet passes into the heating zone.

According to particular methods of implementation, an essentially flattape, or on the contrary a tape shaped to a particular outline, isformed in the first step.

According to one characteristic, the tape is deformed upon itsintroduction into the die, which therefore fulfils the role of a secondshaping device.

According to another characteristic, at least one second thermoplastic,which has been conditioned by an extruder, is introduced into the die.Such a thermoplastic may especially be a polyolefin or polyvinylchloride.

According to another characteristic, the profile is cooled in order tofix its dimensional characteristics and its appearance, and to deliverthe finished profile.

According to another characteristic, the profile is cut up at the end ofthe manufacturing line in order to be stored.

As regards the apparatus for implementing the process, this isessentially characterized in that it comprises:

-   -   means for bringing together in a parallel manner continuous        yarns based on continuous glass fibres and on a first        thermoplastic, and means, especially heating means, for forming        at least one consolidated tape in which the glass fibres are        impregnated with the first thermoplastic; and    -   a die sized to the cross section of the profile and means for        simultaneously introducing at least one tape and at least one        second molten thermoplastic organic material into the said die        in contact with the tape or tapes, so as to obtain a profile        consisting of at least one second thermoplastic organic material        reinforced with at least one tape.

According to one embodiment, the apparatus comprises:

-   -   means for entraining the continuous yarns consisting of        reinforcing filaments and filaments of a first thermoplastic and        means for bringing the said continuous yarns together into the        form of at least one sheet;    -   means for heating at least one sheet to a temperature reaching        at least that of the melting point of the first thermoplastic,        but not the softening temperature of the glass filaments;    -   a device for impregnating at least one heated sheet so as to        distribute the first molten thermoplastic uniformly and allow        the glass filaments to be impregnated therewith.

According to one characteristic, the apparatus includes heating meansconsisting of ovens.

According to another characteristic, the means for bringing the yarnstogether consist of a comb, the tines of which produce auniformly-spaced parallel alignment of the yarns.

According to another characteristic, means for regulating the tension inthe yarns are provided upstream of the means for bringing the yarnstogether.

According to an advantageous variant, an anti-static device is providedupstream of the heating means.

According to another characteristic, the impregnation device comprisesthree members which are arranged in a triangle and between which thesheet runs, the member separation height being adapted in order to applysuitable pressure to the surface of the sheet. The members may berotating heated rolls or stationary heated bars.

Advantageously, each roll has a blade for scraping off the moltenthermoplastic deposited on the roll after the sheet has passed.

According to another characteristic, the apparatus includes a firstdevice for shaping at least one sheet so as to convert it into at leastone tape.

According to another characteristic, the shaping device comprises a die,which is advantageously heated, and/or rollers between which the sheetof yarns runs.

One particular shaping device also centres the sheet and comprises alower roller and an upper roller which are offset one above the otherand rotate in opposite directions, the upper roller being in the form ofa hyperboloid, and the sheet being concentrated around the centralrunning axis as it passes between the two rollers in order to deliver atape constituting a mutually contiguous association of yarns.

According to yet another characteristic, the apparatus according to theinvention includes, upstream of the die by means of which the secondthermoplastic(s) is (are) formed, or this die itself includes, means forpositioning and/or shaping at least one tape for making it come intocontact with at least one second thermoplastic.

According to one embodiment, the die includes means for bringing thesecond molten thermoplastic into contact with the tape by applying anoverpressure thereto.

According to another characteristic, an extruder delivers at least onesecond molten thermoplastic into the said die.

According to yet another characteristic, the apparatus includes a devicefor cooling the profile, especially by exposure to air or to a coolantand/or by contact with members having cold or cooled surfaces, making itpossible to freeze the second thermoplastic(s) and/or the firstthermoplastic and to mutually consolidate the yarns and form the finalprofile.

In particular, the apparatus may include a cooling calender, especiallyconsisting of two rotating cooling rolls which are arranged one abovethe other and which do not have guiding edges, the calender thus givingthe profile its final shape.

Advantageously, the apparatus may include a cold or cooled die,generally having the same outline and the same dimensions as the firstdie receiving the tape and the second thermoplastic(s).

According to an advantageous characteristic, the apparatus may includemeans for spraying liquid, which would make it possible to cool therunning profile.

DESCRIPTION OF THE DRAWINGS

Further advantages and characteristics will now be described with regardto the drawings in which:

FIG. 1 is a schematic side view of the apparatus for manufacturing atape according to the invention;

FIGS. 2 to 6 are perspective views of certain parts of the apparatusshown in FIG. 1, respectively, of a device for regulating the tension inthe yarns, the rotating impregnation device, two variants of the firstshaping device and of the second shaping device;

FIG. 7 shows the variation in mechanical properties as a function oftemperature of a profile obtained according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

The apparatus 1 seen in FIG. 1 allows manufacture of a profile 10according to the invention, which consists, on the one hand, of at leastone tape of continuous reinforcing yarns arranged so as to be mutuallyparallel and contiguous and consolidated together by a firstthermoplastic, and, on the other hand, of at least one second plastic inintimate contact with the said tape(s).

Each yarn, sold by Vetrotex under the brand name TWINTEX® andmanufactured according to the process described in Patent EP 0,599,695,consists of glass filaments and of filaments of a thermoplastic organicmaterial, of the polyolefin or polyester type, which are intimatelyco-mingled.

The manufacturing apparatus 1 comprises, in the form of a line and goingfrom the upstream end to the downstream end, a creel 20 provided withseveral wound packages 2 of yarn 11, an eyeletted plate 30, a device 40for regulating the tension in the yarns, a comb 50, a device 60 forremoving static electricity, an oven 70, an impregnation device 80, afirst shaping device 100, especially a die, a second shaping device,especially a die 200, an extruder 300, a calender 110, a cooling tank120 and a caterpillar haul-off 130.

The purpose of the creel 20 is to uncreel the yarn 11 from each package2. It may be of the unreeling type and be composed of a frame providedwith horizontal rotating spindles 21, each supporting a package 2.

As a variant, it is possible to use a pay-out creel, but this induces atwist into the yarn which is not constant, ranging from one turn per 50cm to one turn per 1 m. This twist has the effect of limiting theminimum thickness of the finished tape, it not being possible inparticular for this to go below 0.3 mm in the case of packages of 982tex yarn. Furthermore, this twist favours entanglement of the yarns asthey run along the tape manufacturing line, thereby causing knots and/ornon-parallel and non-taut yarns 11 in the tape once it has been formed.

Consequently, it may be preferred to use an unreeling creel, inparticular for producing a small tape thickness (of less than 0.2 mm).However, in this case it proves to be necessary to provide a regulatingdevice, referenced 40 in FIGS. 1 and 2, which makes it possible toadjust the overall level of tension in the sheet of yarns.

The eyeletted plate 30, which can also be seen in FIG. 2, lies in avertical plane parallel to the rotating spindles 21 of the creel. Itmakes it possible to group together the yarns 11, each of which passesthrough an eyelet 31 in order to be guided towards thetension-regulating device 40 at an angle appropriate to the desiredtension. The eyelets 31 are made, in a known manner, of a ceramic inorder to prevent the yarns from being damaged as they pass through them.

The tension-regulating device 40 which is illustrated in FIG. 2 iscombined with the eyeletted plate 30. It comprises a series ofcylindrical bars 41 arranged in a staggered configuration one aboveanother, the yarns 11 coming from the eyeletted plate 30 travelling overand under these bars so as to define identical sinusoids, the amplitudeof which influences the tension in the yarns. The height of the bars canbe adjusted so as to be able to modify the amplitude of the sinusoids,an increased amplitude imposing a higher tension in the yarns.

The bars are advantageously made of brass or of a ceramic in order tolimit the static electricity phenomena induced by the rubbing of theyarns. Placed at the exit of the device 40 is a comb 50 whose tines 51group the yarns 11 together into a uniformly-spaced parallel alignmentin order to obtain a sheet 12 in the form of bundles of yarns.

Installed between the comb 50 and the entrance of the oven 70 is anelectrical device 60 serving to remove any static electricity with whichthe yarns 11 might be charged, so as to prevent the said yarns frombulking which, otherwise, would cause them to degrade in the oven 70.

The oven 70 operates by convection of hot air. It could just as well bean infrared oven.

By passing through the oven 70, the sheet 12 is heated to a temperaturesuch that on leaving the oven the sheet has a temperature high enough toreach the melting point of the thermoplastic of the yarns 11 so that themolten thermoplastic sticks together and is embedded in the glassfilaments of the entire sheet 12.

The oven 70 may consist of two successive ovens: a first oven upstreamof the second with respect to the running direction. The purpose of thefirst oven is to heat the sheet 12 as described above and the purpose ofthe second oven is to condition the sheet to a lower temperaturesuitable for introducing the sheet into the shaping device 100.

Located after the oven 70 there is a rotating impregnation device 80which flattens the sheet 12 so as to expel the air contained between theyarns, distribute the molten thermoplastic uniformly over the width ofthe sheet and guarantee that the glass filaments are completelyimpregnated with the thermoplastic.

The impregnation device 80 consists of three members arranged in atriangle between which the sheet 12 runs. In a first embodiment, themembers may consist of stationary bars, the separation of which isadjusted in order to control the pressure needed for the impregnation.The bars may be heated in order to maintain the thermoplastic at atemperature at which it is malleable but without sticking to the surfaceof the bars. For this purpose, the surface may be made of a suitablematerial or else be specifically treated.

In a variant, which can be seen in FIG. 3, the device 80 consists ofthree mutually parallel rolls 81 arranged in a triangle so as to havetwo lower rolls and one upper roll. The rolls are heated and reach atemperature high enough to maintain the thermoplastic of the sheet in amalleable state.

The rolls 81 rotate, the lower ones rotating in the positive directionwith respect to the running direction F of the sheet 12 while the upperone rotates in the opposite direction, the rotation speeds beingidentical and corresponding to that at which the sheet runs.

The height of the upper roll can be adjusted in order to apply pressureto the sheet 12 high enough to ensure that the glass is impregnated withthe thermoplastic.

Since the rolls 81 are in contact with the sheet, a film ofthermoplastic is rapidly deposited onto their surfaces. Advantageously,the said rolls each have a blade 82 whose action is to scrape theirsurfaces and whose purpose is at the same time to prevent the formationof any spurious winding of the glass filaments and to help in achievinghomogeneous distribution of the molten thermoplastic along the length ofthe tape. Thus, should there be an excessively thick film on each roll,this excess is used to supplement the encapsulation of the glassfilaments which might be insufficiently coated.

The inclination of the blades 82 can be adjusted so as to optimize theireffectiveness.

As a variant, for the same purpose of regulating the distribution ofthermoplastic, instead of using the blades 82 the three rolls are drivenat a slightly lower speed of rotation than the speed at which the sheetruns. This solution means that not only do the rolls 82 have to bedriven but also that a speed control mechanism has to be installed.

Note that it would be conceivable to use an oven in which theimpregnation device 80 would be housed, the impregnation device beingable to withstand the temperature of the oven.

Placed at the exit of the oven is a first shaping device 100 which maycomprise a die of sized cross section suitable for shaping the sheet tothe desired shape and dimensions of the tape. Depending on variousembodiments, the die orifice may be approximately rectangular, in orderto form a flat tape, which may possibly be deformed thereafter, or maybe of more complex shape in order to form a tape shaped according to aparticular profile. The die orifice is advantageously made in aremovable part which is fixed to a stationary support, thereby making iteasy to clean and replace.

Advantageously, the die is heated in order to maintain the shapingsurfaces at a temperature close to the melting point of thethermoplastic of the sheet or the temperature at which the thermoplasticis malleable. For example, it is heated by one or more electricalresistance band heaters wrapped around one or more zones of the die.

FIG. 4 shows a first shaping device 100 consisting of a die. The lattercomprises an approximately cylindrical body 105 having a wide opening107 upstream, via which the sheet 12 is introduced, a cavity 106, thewidth of which is constant and the height of which decreases down to thedesired thickness of the tape to be formed, and, downstream, an exit 108via which the tape 13 formed leaves. Part of the approximatelycylindrical body 105 is placed in a heater unit 109. The heating mayespecially be provided by electrical resistance elements in the form ofband heaters placed around the heating unit 109 and possibly around thatpart of the approximately cylindrical body 105 which extends beyond theheater unit 109.

As a variant, the shaping device 100 may comprise rollers of variousshapes between which the sheet of yarns runs. Although it is alsopossible to manufacture a shaped tape according to this variant, it ismore particularly intended for the production of a flat tape.

Thus, the device according to this variant comprises, as illustrated inFIG. 5, a cylindrical lower roller 101 and a hyperboloidal upper roller102 which is slightly offset upstream with respect to the verticalthrough the lower roller, both rollers rotating and being heated inorder to maintain the temperature at which the thermoplastic of thesheet 12 is malleable.

The purpose of the device 100 is to convert the sheet 12 into a tape 13of constant thickness formed by bringing the yarns 11 together so as tobe touching, in order to create transverse continuity in the said tape.Thus, the device 100 concentrates the sheet around the central axis ofthe line in order to reduce its width, which had been increased duringits passage through the impregnation device 80, and recentres the sheetwith respect to the central axis of the manufacturing line in order tosuitably guide the tape downstream towards the calender 110.

The gathering and guiding towards the centre is achieved by thehyperboloidal shape of the upper roller 102 which, by adjusting itsheight, also allows light pressure to be applied to the upper surface ofthe sheet in order to concentrate it.

The counterrotation of the rollers 101 and 102 firstly prevents thethermoplastic from drying and secondly prevents it from accumulating,which could impair the uniformity of its distribution and consequentlythe thickness of the tape.

Located after the first shaping device 100 is a second shaping device200, which can be seen in FIG. 6. The shaping device 200 is a die fed,on the one hand, with at least one tape 13 obtained as described above,and, on the other hand, by a means 300, especially an extruder known tothose skilled in the art, which delivers, under pressure, at least onesecond molten thermoplastic organic material 30.

FIG. 6 shows a partially exploded cross section of the shaping device200, shown in perspective. The cross section is made perpendicular tothe plane of the tape 13, and in the running direction of the tape 13.The exploded part makes it possible to show the means 300 for deliveringthe thermoplastic 30 and the path of the latter through the shapingdevice 200.

The shaping device 200 consists of an inlet 201 for a tape 13,introduced in the direction of the arrow F1, and of an inlet 211 for thesecond thermoplastic 30, introduced in the direction of the arrow F2.

The tape 13 runs through a cavity 202 and then into a cavity 203.

The thermoplastic 30 travels through the channels 212, 213 located awayfrom the cavity 202. These channels are intended to feed the cavity 203with thermoplastic 30 from several sides.

The channels 212, 213 include restrictions 214, 215 in order to run intochannels of smaller cross section than that of the channels 212, 213.Thus overpressures may be created in the molten thermoplastic 30.

The channels run into the cavity 203.

The latter cavity 203 is bounded by walls 218, 219 consisting ofinclined planes which terminate in an outlet 204. Thus, a convergentsystem is obtained which makes it possible to deliver the thermoplastic30 in contact with the tape 13. The overpressure P applied makes itpossible to create an intimate contact between the thermoplastic 30 andthe tape 13, while preventing any backflow of the thermoplastic towardsthe upstream.

The cavity 203 may be designed so that the thermoplastic 30 convergesuniformly in all directions around the tape 13. To obtain this function,it is especially possible to use a frustoconical guide having includedwalls 220, 221 which is located around the cavity 202.

It is thus possible to direct the stream of thermoplastic 30 so as toposition a tape 13 in a desired configuration and thus obtain a profile14 in which the reinforcement is placed in a defined geometry accordingto the chosen applications.

It should be noted that the position of the extruder 300 shown here as acrosshead is in no way limiting. This is because it may be located atany position about the axis of travel of the tape 13.

Furthermore, an apparatus for implementing the process may also beenvisaged in which the extruder is placed along the direction in whichthe profile runs. In particular, it may be envisaged that the extruder300 delivers thermoplastic 30 along the running axis of the profile 14,10 and in which at least one tape 13 is brought into at least any onedirection and converges on the running axis of the profile 14, 10 afterit has penetrated the shaping device 200.

It is thus possible to obtain profiles 10 reinforced with several tapes13.

A device 110 is located downstream of the device 200 which guides theprofile 14, the cooling of which starts right from the die exit incontact with the ambient air, towards the specific cooling means for thepurpose of fixing the dimensional characteristics of the profile andgiving it its final appearance so as to have a finished profile 10. Thedevice 110 cools the profile 14 in order to freeze the secondthermoplastic, giving it a smooth surface appearance.

This device 110 may be a calender consisting of rolls, possibly cooledby internal circulation of water. More advantageously, this will be acold die having the same outline and the same dimensions as the hot die100, its temperature possibly being between room temperature and 200°C., for example.

The final cooling of the tape is achieved by means of the cooling tank120, especially a water tank, located after the calender 110, throughwhich tank the profile 14 passes as it runs along. The tank 120 mayinclude means for spraying the coolant onto the profile 10.

During all its cooling operations, the entire mass of the secondthermoplastic freezes, as does the first thermoplastic, in order toconsolidate the yarns and to bind the fibrous reinforcements to thematrix of the second thermoplastic.

Installed beyond the cooling tank is a caterpillar haul-off 130 whichconstitutes, in a known manner, a means of entraining the yarns and thetape, by exerting a tensile force all along the line. It sets thepay-out speed and the run speed of the sheet and then of the tape.

Finally, the manufacturing apparatus 1 may include, at the end of theline, a saw intended to cut the profile, so as to make it easier tostore it.

The process may be implemented in the following manner.

The start-up of the process begins by manually pulling each yarn 11 offthe packages 2 and manually taking it as far as the haul-off 130 whereeach yarn is then held clamped, all the yarns passing through thevarious devices described above. In this example of application, thereare 35 rovings of glass/polyester co-mingled composite yarn having thetrademark TWINTEX®, the 860 tex overall linear density of whichcomprises 65% glass by weight. The polyester, especially polyethyleneterephthalate, therefore constitutes the first thermoplastic.

The oven 70 and the heating elements of the device 1 are raised intemperature in order to reach a temperature well above the melting pointof the polyester, i.e. 254° C. in the case of polyethyleneterephthalate.

The other means operate at the following temperatures:

-   -   members of the impregnation device 80: 290° C.;    -   rollers of the shaping device 100 according to the embodiment        illustrated in FIG. 4: 270° C. to 300° C.;    -   shaping device 100 according to the embodiment with a die: 310°        C.;    -   second shaping device 200: 190 to 200° C. in that zone where the        intimate contact between the tape 13 and the second        thermoplastic 30 takes place.

The haul-off 130 is switched on and pay-out from the packages 2 starts.

The yarns 11 pass through the eyelets 31, then astride the bars in thedevice 40 and are brought together through the tines of the comb 50 inorder to form, at the exit, the sheet 12 of parallel yarns.

The sheet 12 then meets the device 60 which removes any staticelectricity.

Next, the sheet enters the oven 70 so that the first thermoplasticreaches its melting point. Thereafter, it passes between the heatedrolls of the device 80 which make it possible for it to be rolled,expelling the air, and for the thermoplastic which thus encapsulates theglass filaments to be uniformly distributed. We should point out thatthe amount of thermoplastic does not have to be metered since it isdirectly incorporated into the raw material of the tape by it beingco-mingled with the glass filaments. The temperature of the sheet, afterit has passed through this device 80, is from 260 to 270° C.

The sheet 12 then runs between the rolls or through the die of the firstshaping device 100 in order to convert it into a tape 13, shaped byclosing up the yarns against each other and placing them so that theytouch each other. After shaping, the tape has a temperature of 270 to280° C.

A tape 13 then enters the second shaping device 200 after a travel whichcools it slightly, especially down to about 210° C.

The said device 200 is fed simultaneously with a second thermoplastic30.

The contact between the tape 13 and the second thermoplastic 30 takesplace at about 190° C. to 200° C.

Next, the profile 14 passes between the rolls of the cold calender 110which fixes its final shape, by freezing the surface of the secondthermoplastic and consolidating the yarns. The profile 10 of theinvention is obtained with a constant thickness and a smooth appearance.The profile has a temperature of 100° C. on leaving the calender.

In order to facilitate and speed up the cooling of the entire profile10, the latter passes through a coolant contained in the tank 120 andbecomes, on leaving it, its temperature being 30° C., a solid productsufficiently rigid to be cut up, for ease of storage, transportation anduse.

Composite profiles are therefore obtained in which there is an intimatebond between the reinforcing tape and the matrix consisting of thesecond thermoplastic. When the applied pressure P is high enough, theprofile obtained contains no porosity.

To illustrate the benefit of the products obtained by the processdescribed above, profile manufacturing trials were carried out andspecimens of these profiles were subjected to mechanical tests.

The profiles manufactured for these tests were solid.

The specimens tested had a rectangular cross section 30 mm in width and7.5 mm in thickness.

The reinforcing tape measured about 18 mm in width and 1 mm inthickness. A wide face of the tape was located 1 mm from a first wideface of the specimen. The tape was then covered with the secondthermoplastic with a thickness of about 5.5 mm from one side and 1 mmfrom the other side.

The tape was centred on the width of the profile, and thereforesurrounded over its width by about 11 mm with the second thermoplastic.

The second thermoplastic was polyvinyl chloride (PVC).

Mechanical strength tests in 3 point bending specimens of 30×7.5 crosssection as indicated above, with a distance between supports equal to 20times the thickness of the specimen, carried out at room temperature,according to the ISO 14125 standard, made it possible to determine theelastic modulus of the profile, [namely: E_(profile)=3600±200 MPa.

In comparison, a profile of PVC alone having the same dimensions had anelastic modulus of E_(PVC)=2650 MPa.

The effect of the reinforcing tape results in an increase in the elasticmodulus of the order of 40%.

It is possible to optimize the increase in the modulus of the profiledescribed by shifting the axis of the reinforcing tape with respect tothe axis of the neutral fibre of the profile. A second series of trialscarried out on profile specimens of the same dimensions, in which thereinforcing tape was further away from the axis of the neutral fibre ofthe profile, thus made it possible to obtain the following results:

E_(profile)=4800±100 MPa, i.e. an increase in the elastic modulus ofabout 80%.

A third series of specimens was produced with a profile having twice thethickness of the previous one, i.e. 15 mm, in which two reinforcingtapes 1 mm in thickness and 18 mm in width were inserted.

The external wide faces of the two tapes were located 1 mm from the wideedge of the profile. There were therefore about 11 mm of second plasticbetween the internal edges of the two tapes.

For this profile, the following elastic modulus was therefore obtained:

E_(two-tape profile)=7350±200 MPa.

The increase in the elastic modulus over PVC alone is almost a factor of3.

Further mechanical strength tests in 3 point bending were carried out ona fourth series of specimens, varying the temperature of the specimen.

The specimens tested had a rectangular cross section 13 mm in width and3.7 mm in thickness, the reinforcing tape having a thickness of about 1mm still being located about 1 mm from a first face of the specimen. Thedistance between supports was therefore 48 mm.

The mechanical tests carried out within a 30 to 120° C. temperaturerange made it possible to determine the elastic modulus of the profileat each of the test temperatures. The variation in the modulus is shownin FIG. 7 by the solid curve for a profile reinforced according to theinvention and by a broken line for an non-reinforced profile. FIG. 7shows the relative modulus variations, which is why the two curves startfrom the same starting point at 30° C.

Given the relatively unfavourable geometry of the profile with areinforcement located relatively close to the axis of the neutral fibreof the profile, the difference in modulus at room temperature is,however, relatively less pronounced than in the previous series oftests.

In the case of the non-reinforced PVC specimen, a very rapid reductionin the elastic modulus is observed when the temperature increases, witha glass transition at a temperature of around 100° C. By way ofindication, the modulus is of the order of 1000 MPa at 80° C. and of theorder of a few MPa at 120° C.

For the reinforced PVC specimen, a degree of stability of the elasticmodulus is observed when the temperature increases, at least up to70-80° C., with a less rapid drop for the higher temperatures with,furthermore, a glass transition at a temperature of around 90° C. By wayof indication, the modulus is greater than 2000 MPa at 80° C. and around500 MPa at 120° C.

It has thus been demonstrated that there is excellent load transferbetween the thermoplastic matrix and the reinforcement at roomtemperature and at high temperature.

Without wishing to be bound by this explanation, it is assumed that itis the excellent cohesion provided by the various steps of the process,and especially the construction of a tape from glass fibres and organicfibres, which gives these remarkable properties.

The methods of implementation and the embodiments described above are inno way limiting and it is possible to envisage, in particular,manufacturing a profile in which the reinforcing tape is notsubstantially flat but assumes an angular or curved configuration.

It is thus possible to envisage manufacturing plastic pipes, for examplemade of polypropylene, with an internal, median, or external tubularreinforcement, intimately mixed with the plastic of the pipe. Thetubular reinforcement consists of a tape formed from continuous yarns inwhich the thermoplastic is advantageously polypropylene in the case ofthe example, the tape being wound along its running axis prior to orconcomitantly with its passage through the extrusion die. The plastic ofthe pipe may advantageously be chosen, treated or combined with anothermaterial so as to give a particular appearance or feel, especially witha coating of elastomer.

The process according to the invention can thus be applied to theproduction of rods, rails, pipes or hoses, covering materials such asweatherboards (wall cladding), stakes, etc.

1. A process for manufacturing a composite profile based on athermoplastic organic material reinforced by reinforcing fibres,including making a multiplicity of continuous reinforcing yarns comeinto contact with a thermoplastic organic material and shaping thecomposite profile, comprising: bringing together continuous yarns basedon continuous glass fibres and on a first thermoplastic to be paralleland forming at least one consolidated tape by heating the continuousyarns, wherein in the at least one tape glass fibres are impregnatedwith the first thermoplastic; and introducing the at least one tape intoa first cavity of a die and simultaneously introducing at least onesecond molten thermoplastic organic material into a second cavity of thedie, wherein the second cavity is separated from the first cavity by atleast one frustoconical guide, the frustoconical guide includes arestriction portion configured to prevent backflow of the second moltenthermoplastic organic material into the first cavity, thereby causingthe second molten thermoplastic organic material to come into contactwith and fuse to at least a top and bottom portion of the at least onetape in the second cavity; and outputting a second tape having a profileof at least one second thermoplastic organic material reinforced by theat least one tape.
 2. The process according to claim 1, wherein the atleast one tape is fonned from continuous yarns comprising glass yarnsand organic fibres of the first thermoplastic.
 3. The process accordingto claim 1, wherein the continuous yarns that are brought togetherinclude continuous glass filaments and continuous filaments of the firstthermoplastic that are co-mingled together.
 4. The process according toclaim 1, wherein the bringing together comprises: entraining andbringing together continuous yarns based on the first thermoplastic andon the glass fibres in a parallel manner in a form of at least onesheet; causing the at least one sheet to enter a zone to be heated to atemperature reaching at least a melting point of the first thermoplasticwithout reaching a softening temperature of the glass fibres; causingthe at least one sheet to pass through an impregnation device, whilemaintaining its temperature at a temperature at which the firstthermoplastic is malleable, to distribute the first molten thermoplasticuniformly and to impregnate the glass fibres therewith.
 5. The processaccording to claim 4, wherein the at least one sheet is introduced intoa first shaping device, while maintaining its temperature at atemperature at which the first thermoplastic is malleable, to obtain theat least one tape formed by bringing the continuous yarns together to betouching, thereby creating transverse continuity.
 6. The processaccording to claim 4, further comprising unreeling, from wound packages,a continuous yarn of reinforcing filaments and filaments of the firstthermoplastic and, while the continuous yarns are being brought togetherin the form of a sheet, regulating tension in the continuous yarns. 7.The process according to claim 4, further comprising stripping thecontinuous yarns of any static electricity before the at least one sheetpasses into the heating zone.
 8. The process according to claim 1,wherein the profile is cooled to fix its dimensional characteristics andits appearance to deliver the profile.
 9. The process according to claim1, further comprising cutting up the profile at an end of amanufacturing line, to be stored.
 10. The process according to claim 1,wherein the first thermoplastic is a polyester and the secondthermoplastic is polyvinyl chloride.
 11. The process according to claim1, wherein the second molten thermoplastic organic material convergesuniformly from all directions around the tape.